diff --git a/stack.yaml b/stack.yaml
index 701474a..3b03c93 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -17,8 +17,8 @@
 #
 # resolver: ./custom-snapshot.yaml
 # resolver: https://example.com/snapshots/2018-01-01.yaml
-resolver:
-  url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/16/15.yaml
+resolver: lts-17.5
+#  url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/16/15.yaml
 
 # User packages to be built.
 # Various formats can be used as shown in the example below.
diff --git a/stack.yaml.lock b/stack.yaml.lock
index b10e8c4..1bba64b 100644
--- a/stack.yaml.lock
+++ b/stack.yaml.lock
@@ -3,11 +3,10 @@
 # For more information, please see the documentation at:
 #   https://docs.haskellstack.org/en/stable/lock_files
 
-packages: []
 snapshots:
-- completed:
-    size: 532380
-    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/16/15.yaml
-    sha256: 3b5f2a699aa5ed3abbc30410062bf743926f0868ce3eeb5655370c6c6cc1a9f4
-  original:
-    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/16/15.yaml
+- original: lts-17.5
+  completed:
+    sha256: 78e8ebabf11406261abbc95b44f240acf71802630b368888f6d758de7fc3a2f7
+    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/17/5.yaml
+    size: 565266
+packages: []